What is the flood season?
How can it be counted as flood?
Look down together!
What is the flood season?
Floods in rivers and lakes are clearly concentrated throughout the year, and are prone to periods of flooding disasters. Due to the different geographical locations of the rivers and the different flood seasons, the length and timing of the flood seasons are also different.
How to determine the flood date?
The flood-entry date refers to the start date of the flood season that year.
The flood-entry date is determined by two indicators: rainfall and water level, comprehensively considering the rules of my country’s heavy rains and floods, and in accordance with the “Measures for the Determination of my country’s Flood-entry Date” formulated by the Ministry of Water Resources, the flood-entry standards are as follows:
The flood entry standard starts from March 1 every year, when the flood entry index meets one of the following conditions, the day can be determined as the flood entry date.
1. For 3 consecutive days, the area covered by the rain area with a cumulative rainfall of 50 mm or more reaches 150,000 square kilometers;
2. Any one of the representative stations for important rivers entering the flood season exceeds the warning water level. If the warning water level of the representative station changes, the latest indicator will be used.
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According to the season and cause of the flood
Flood season can generally be divided into four types
Spring flood season
In spring, the flood period is mainly caused by the melting of icebergs in the northern river source or the upper frozen ice cover, and the flood period caused by the rainy season at the turn of spring and summer in the south
Flood season
The flood period mainly caused by heavy rains in summer
Autumn flood season
The flood period mainly caused by heavy rain in autumn (or strong continuous rain)
Freezing season
In winter and spring, the river course is blocked by ice and thawed in the flood period
Due to climatic differences, the start and end times of the flood season are different in various parts of our country. The flood time is generally delayed from south to north as the rain belt changes. July to August is the main flood season in the country.
The Pearl River, Qiantang River, Ou River and the Yellow River, Hanshui River, and Jialing River have obvious double flood seasons. The Pearl River, Qiantang River, and Ou River are divided into pre- and post-flood seasons, and the Yellow River, Hanshui and Jialing Rivers are divided into high and autumn seasons.
Post time: Apr-07-2021